Here are two possible cause-effect diagrams of the relations between adding people to a software project and relative progress.
Use the up and down arrows in the nodes in the model to:
- add some new people
- change your organization such that less coordination between people is required
- reduce the training load on old workers
What happens to relative progress? When do you see changes? Do you like all the changes you see?
Above was a simple model of Brooks’s Law, taken from “How Software is Built” [Weinberg, 2014]. This is is an open-loop system; there are no feedback loops. This makes it a somewhat simple (but interesting) dynamic.
There is a great way managers can transform this system into a system that will be raging out of control in no time. Consider this management intervention, also from [Weinberg, 2014]:
You might recognize this as Brooks’s Law:
Adding manpower to a late software project makes it later.
[Brooks, 1995]: The Mythical Man-Month: Essays on Software Engineering
All causal loop diagrams are models and thus they’re wrong and useful at the same time. You can remix a model to make it more closely represent your context. Please share your remixed model with the world!